1. Field of the Invention
The present invention relates to a capo, for use with a stringed musical instrument to effectively change the key in which the instrument is playing, and to a method of using the capo. More particularly, the present invention relates to a capo having dual adjustability modes including a quick-fix feature, and to a related method, whereby a coarse tightening adjustment can rapidly be made immediately during installation, followed by a fine tightening adjustment effected by rotating a thumbscrew.
2. Description of the Background Art
A number of different capos are known for use with stringed musical instruments, particularly guitars, banjos and the like, which have a neck portion including a fretboard on which the strings are played. The capo is a clamping device which fits on the instrument neck, and which is used to selectively clamp the strings against the fretboard so as to alter the effective length of vibration of the strings, and thereby to selectively raise the respective tones produced thereby.
The capo allows for selective alteration of the tonality of the strings without affecting the original tuning of the instrument. Thus, by placing the capo at a pre-selected location on the fretboard, a musician can play his/her instrument and produce a desired sound quality, since the pitch produced by the strings with the capo attached is different from the pitch produced by the stings with the capo absent. This allows a musician to temporarily change the effective key in which the instrument is playing.
A number of different capos are known and commercially available. Each of these is basically a clamping device in which a padded clamping bar is caused to press transversely across the strings by operation of an adjustable clamping mechanism that interacts with the underside of the neck below the fretboard.
U.S. Pat. No. 608,278 to Benson, dated Aug. 2, 1898, discloses a capo having a generally U-shaped main body, a clamping bar connected to the upper portion of the main body for transversely contacting the fretboard strings, a foot for pressing against the underside of the fretboard, a screw operated clamping mechanism and a guide finger interconnected with the foot and the lower portion of the main body for keeping the foot from turning when the screw of the screw operated clamping mechanism is rotated to effect clamping of the clamping bar onto the strings.
U.S. Pat. No. 656,904 to Pletcher, dated Aug. 28, 1900, discloses a capo having a clamping bar for pressing transversely against the strings, a clasp member pivotally connected to the clamping bar, an arm member connected to one end of the clamping bar, and a spring steel clip pivotally connected with the arm and which is structured to selectively engage the clasp member.
U.S. Pat. No. 775,399 to Halladay, dated Nov. 22, 1904, discloses a capo having a clamping bar for transversely engaging the strings, an arm connected to the clamping bar, and a screw actuated lever clamp pivotally interconnected with the arm.
U.S. Pat. No. 1,007,960 to Moore, dated Nov. 7, 1911, discloses a capo having a clamping bar for transversely contacting the strings, a rod pivotally connected at either side of the clamping bar, and a screw operated foot pivotally connected to the free ends of the rods.
U.S. Pat. No. 4,104,947 to Oster, dated Aug. 8, 1978, discloses a capo having a U-shaped member of which the upper portion thereof serves as a clamping bar for transversely engaging the strings, two off-set resilient string engaging members, a screw operated clamping mechanism connected with the lower portion of the U-shaped member and a foot interconnected with the clamping mechanism and a central portion of the U-shaped member.
U.S. Pat. No. 4,250,790 to Shubb et al, dated Feb. 17, 1981, discloses a capo having a clamping bar with a resilient material for transversely contacting the strings, an arm connected to the clamping bar, a curved jaw pivotally connected to the arm for contacting the underside of the fretboard, a lever pivotally connected to the arm in spaced relation with respect to the curved jaw, and a screw mechanism interconnected with the lever.
U.S. Design Pat. No. D257,988 to Nakamoto, dated Jan. 20, 1981, discloses an ornamental design for a capo showing a yoke having a pivotally connected clamping bar for transversely contacting the strings, a releasable clasp mechanism for holding the clamping bar in fixed relation to the yoke, and a screw operated clamp mechanism which includes a foot for contacting the underside of the fretboard and guide rods for preventing the foot from rotating when the screw is rotated.
U.S. Design Pat. No. D281,508 to McKinney, III, dated Nov. 26, 1988, discloses an ornamental design for a capo showing a yoke having a pivotally connected clamping bar for transversely contacting the strings, a releasable clasp mechanism for holding the clamping bar in fixed relation to the yoke, and a screw operated clamp mechanism which includes a foot for contacting the underside of the fretboard and a guide member for preventing the foot from rotating when the screw is rotated.
U.S. Design Pat. D446,540 issued Aug. 14, 2001 to Elliott discloses another ornamental capo design.
U.S. Pat. No. 5,081,894 to Paige, issued Jan. 21, 1992, discloses a capo including a semi-circular yoke, a clamping bar pivotally connected to a first fork of the yoke and releasably interlocked at the second end to a second fork of the yoke via intermeshing of opposing slots, a clasp mechanism for releasably locking onto an end of the clamping bar, a screw-operated foot connected with the yoke, and dual guide clamping bars connected at either side of the foot which movably engage slots in the yoke. The capo of this reference engages the strings uniformly and simultaneously as the screw is tightened.
In addition to the above, some hand tools are known which use fast-acting dual phase engagement structure. Some examples of fast-acting clamps and other tools can be found in Silver et al., U.S. Pat. No. 150,900; Gordon, U.S. Pat. No. 2,463,263; Hopfeld, U.S. Pat. No. 2,461,687; Phillips, U.S. Pat. No. 3,599,960; Ping, U.S. Pat. No. 6,250,621; Slepekis, U.S. Pat. No. 6,962,099; and Gasparyan et al., U.S. Pat. No. 7,036,807.
While the foregoing examples of capos and other tools are usable for their intended purposes, a need still exists in the art for an improved capo. In particular, there is a need for an improved capo, and method of installing same, which is capable of being installed and adjusted quickly, and which includes both coarse and fine tightening modes.